MRSA is an opportunistic strain of staphylococcus aureus found in healthcare facilities that has a resistance to beta-lactam antibiotics. It is commonly spread by hands and contaminated medical instruments.

VRE is an enterococcus with a developed resistance to vancomycin. It naturally lives in the intestines but can cause serious ailments such as peritonitis in weak patients, which is very difficult to treat.

Serratia marcescens is usually found in the feces or mouth and does not usually infect healthy people. However, it is an opportunistic bacterium that can cause bacteriemia if it enters the bloodstream of sick or recovering patients.

Pseudomonas aeruginosa is an opportunistic bacterium found in most environments, which is associated with infection in patients after surgery. Some strains are showing resistance to beta-lactam and other antibiotics.

Clostridium difficile is a spore-forming bacterium in our intestines. Antibiotics can induce the bacteria to multiply and produces toxins that cause pain and diarrhea. The spores can be washed away but are resistant to hand disinfectant.

E. coli can cause food poisoning from only 100 bacteria. Often found in undercooked foods or transferred while using the toilet, E. coli produces verotoxin to destroy blood vessel walls in the large intestine, causing severe abdominal pain.

Norovirus causes inflammation in the digestive tract and common food poisoning. It is usually acquired from raw shellfish or from an infected person's vomit or feces. As a non-enveloped virus, it is strong against disinfectants.

Rotavirus causes severe diarrhea in children. Almost every child under 2 years without immunity will experience rotavirus. Transmission most commonly occurs when hands are contaminated while handling vomit or diarrhea.

The influenza virus causes the common flu. With continual minor mutations it brings about seasonal epidemics every year. The major routes of infection are from airborne particles from sneezing or from touching contaminated surfaces.

Adenovirus is a non-enveloped virus that causes illnesses such as pneumonia, fever and conjunctivitis. With many subtypes that multiply in the tonsils or lymph nodes, the immune system cannot effectively react, allowing several infections.